Transfer ratio

FIG. 18-23 Relative change in sohd-liqiiid mass-transfer ratio with three different suspension levels, i.e., on-hottom motion, off-hottom motion, and complete uniformity. 

The last arrangement of voltage feedbaek is the isolated feedback. This is used when the input voltage is eonsidered lethal to the operator of the equipment (>42.5 VDC). The two aeeepted methods of eleetrieal isolation are optical (optoisolator) or magnetic (transformer). This seetion will talk about the more eommon method of isolation, when an optoisolator is used to isolate the lethal portions of the eireuit from the operator portion. The optoisolator s Ct (eurrent transfer ratio (or drifts with temperature, ean degrade slightly with age,... 

On the primary side of the power supply, the transistor output of the optoiso-lator will be a simple eommoii-emitter amplifier. The MOC8102 has a typieal eurreiit transfer ratio of 100 pereeiit with a +/- 25 pereeiit toleraiiee. When the TL431 is full-on, 6mA will be drawn from the transistor within the MOC8102. The transistor should be in a saturated state at that time, so its eolleetor resistor (Rl) must be... 

Figure 10-86. Heat transfer ratio correlations for steam and air system. (Used by permission Henderson, C. L, and Marchello, J. M. ASME Transactions Journal of Heat Transfer, V. 91, No. 8, p. 44, 1969. American Society of Mechanical Engineers. All rights reserved.)...

The density-dependent jump in the properties of poly electrolyte brushes has also been fonnd in the transfer ratio and the snrface potential of the brnshes [38], establishing the existence of the density (interchain distancej-dependent transition of polyelectrolytes in solntions. 

Monolayers of l-tert-bntyl-l,9-dihydrofullerene-60 on hydrophobized ITO glass exhibited three well-defined rednction waves at -0.55 V, -0.94 V, and -1.37 V (vs. satn-rated calomel electrode, SCE), with the first two stable to cycling [283]. Improved transfer ratios near nnity were reported. The peak splitting for the first two waves was 65-70 mV, mnch less than reported for the pnre C60-modified electrodes. The rednction and oxidation peak cnrrents were equal however, the peak currents were observed to be proportional to the sqnare root of the scan rate instead of being linear with the scan rate as normally expected for snrface-confined redox species. 

Transfer experiments of the Langmuir films onto solid substrates and the preparation of LB films were investigated for 43. The deposition of films of 43 occurred regularly on quartz sHdes or silicon wafers with a transfer ratio of 1 0.05. The diblock structure of dendrimer 43 also appeared crucial for efficient transfers of the Langmuir films in order to obtain well-ordered multilayered LB films. Effectively, the transfer of the Langmuir films of the dendrimer 42 with the small polar head group was found to be difficult with a transfer ratio of about... 

We review useful usages of a quartz crystal-microbalnce (QCM) as tool of in situ characterization of Langmuir-Blodgett (LB) films transfer ratio and water incorporation during a transfer process, swelling behavior in water subphase, and detachment at the air-water interface. 

EVALUATION OF LB FILMS DURING A TRANSFER PROCESS TRANSFER RATIO AND WATER INCORPORATION... 

Figure 2 also indicates that we should wait ca. 15 min to get the dry LB films during transfer processes in this conditions. When the next deposition was carried out before the complete evaporation of water, a transfer ratio of LB films was gradually decreased from 0.9 to 0.7 with increasing dipping cycles. 

At the low surface pressures of 5 and 10 mN m->, the observed values showed the deviation from the theoretical lines and the transfer ratios were ca. 0.9 - 0.7. The transferred mass obtained... 

The W2 and v values at the 5th dipping cycle were obtained at various surface pressures, and the results are shown in Figure 5. Both W 2 and v values increased with decreasing the surface pressure. At the low surface pressures below 20 mN m-i, the LB films having many defects were transferred with a low transfer ratio below 1.0, and the large amount of water was incorporated in these defects and its evaporation speed was fast through the disordered film. 

W 2 and v values at the 5th transfer cycle of cadmium octadecanoate at 20 mN m-i as a function of dipping speed of the QCM substrate are summarized in Table 1. The transfer ratio of LB films (W,) was 0.95 0.05 at the dipping speeds of 40 - 100 mm min. When the dipping speed was decreased, the evaporation speed (v) was decreased the well-oriented LB films could be obtained at the low dipping speed. This is consistent with the report by Pitt, et. al. that the lower transfer speed was favorable to obtain the higher quality LB films in the first 10 layers [31]. 

The W2 and v values for LB films prepared from various aliphatic acid cadmium salts having different alkyl-chain lengths (C)6 - C22) were also obtained and the results are shown in Figure 6. All LB films could be transferred with the transfer ratio of 1.0 0.1 in these conditions. The W2 value was constant and independent of the chain length, but the v value decreased with decreasing the chain length. This indicates that the chain length of lipids mainly affects the evaporation speed of water in LB interlayer and has no effect on the amount of the incorporated water. 

LB films of various lipids were transferred on a QCM as a substrate under various conditions. The mass of the transferred film (W, the transfer ratio), the amount of incorporated water (W 2), and the evaporation speed (v) were evaluated from the frequency changes of the QCM during transfer processes in situ. We could estimate the deposition state and structures of LB films from these values. When the LB films deposited at the lower surface pressure and at the higher dipping speed on the more hydrophilic surface, the smaller transfer ratio and the larger amount of incorporated water, and the larger evaporation speed of the water were observed, which indicates the deposition of the disordered LB films. On the contrary, when the well-packed LB films are obtained, the good transfer ratio (W ), the small W2... 

Surface pressure (mN m-1) Transfer ratio Detached amount 1 (ng)... 

FIGURE 1.19 Circuit diagram (upper panel) and current transfer ratio, I0jl (lower panel) of the polymer optocoupler. The photodiode was biased at —10 V. 

The transfer ratio is not only dependent on the charge of the probe and analyte ions, but also on their electrophoretic mobilities. This is due to Kohlrausch s regulating function (KRF),... 

---